Roller-mill.



'- (a. c. MCI-151103..

ROLLER MlLb v APPLICATION FILED APR. n. 1917.

mm Apr. 30,1918;

2 SHEETS-SHEET I IN VENTOR Wmwyw MfiM/wmmds WITNESSES:

ATTORNEYS G. C. RICHARDS.

ROLLER MILL.

APmcAnoN FILED APR.17| 19 n.

Patented Apr. 30. 1918.

2 SHEETS-SHEET 2.

1? 5 5 INVENTOR WITNESSES:

a is to provide a simple,

GEORGE C. RICHARDS, OF BERKELEY, CALIFORNIA.

ROLLER-MILL.

Specification of Letters Patent.

Patented Apr. 3d, 1918..

Application filed April 17, 1917. Serial N 0. 162,742.

To all whom it may concern:

Be it known that I, GEORGE C. RICHARDS, a citizen of the United States,residing at Berkeley, in the county of Alameda and State of California,have invented new and useful Improvements in Roller-Mills, of which thefollowing is a specification.

This invention relates to a grinding mill of the centrifugal rollertype.

One of the objects of the present invention compact grinding mill of thecentrifugal roller type, which is particularly adapted for pulverizingand amalgamating gold ores for recrushing the tailings for jigs andreducing the ore for concentration. Another object of the invention isto provide an annular grinding pan'eme ploying renewable and bottom diesand a plurality of cone-shaped grinding rollers supported in the panwithout journals and having rinding faces formed thereon engageable bothwith the end and the bottom dies. Another object of the invention is toprovide a plurality of propelling arms, one for each roller, and a shoefor each arm engageable with the roller and having three functions:First, each shoe forms a driver for the roller; second, each shoe formsa grinding face between the roller and the shoe; and, third, each shoeforms a grinding face between the shoe and the bottom dies. Anotherobject of the invention is to pro: vide a continuous slanting annularscreen discharge of large area and capacity. Further objects willhereinafter appear.

The invention consists of the parts and the construction and combinationof parts as hereinafter more fully described and claimed, havingreference to the accompanylng drawings, in which Figure 1 is a central,vertical section through the grinding mill.

Fig. 2 is a plan section on line 2-2 of Fig. 1.

Fig. 3 is a perspective detail view of a grinding unit comprisin aroller and a shoe.

Fig. 4 is a vertical, ongitudmal section through one of the grindingr01lers.

Referring to the drawings in detail, A mdicates a circular pan, in thebottom of which is placed a suitable number of removable and renewabledie plates 2. Formed around the outer edge of the pan'is an annular rim3, and'supported a ainst said rim, interiorly thereof, is a plura 'ty ofremovable and renewable end dies 4. Extending upwardly from the annularrim section 3 is a plurality of arms 5, and supported by said arms isan. upper housing 6 which supports a cover plate 7.

Formed in the center portion of the pan is a'bearing S, and extendingthrough said bearmg and a second bearing formed in the cover plate 7 isa driving shaft 9, to which power may be transmitted in any suitablemanner, or, as here shown, by means of a pair of bevel gears 10. Keyedor otherwise secured to the shaft and supported against endwise movementby the upper end of the bearing 8 is a hub member 11, and formedintegrally therewith is a plurality of down, wardly extending, radiallydisposed arms 12.

Suitably secured within the housing 6 is a centrally disposed feedinghopper 13, and extending through the cover plate 7 is a feed launder l4and a water pipe 15, both of which discharge into the hopper 13, whichin turn delivers the material to be ground to the central portion of thepan where it is gradually distributed and ground by a plurality ofcone-shaped rollers 16. These rollers consist of an inner east-iron coremember 17 and an exterior roller shell 18 which may be made of forgedand roller chrome steel, or other suitable material, and as thick asdesired. The outer end of each shell is tapered, as shown at 19, toengage the end dies in the pan, in this manner forming a grinding facebetween saiddies and the ends of the roll ers which has been foundhighly efficient as it adds considerably mill.

Pivotally mounted on the lower end of each arm 12 is a shoe, consistingof a bottom plate 20 and a front plate 21. These plates are preferablyformed integral and each is provided with a removable and renewable dieplate, such as shown at 22 and 23, re;- spectively. The shoes aremounted behind the rollers and as they are pivotally mounted in the arms12, which revolve with the drivwill engage the rear sides of the rollersand push or roll the same around the pan. In other words, each shoeforms a driver for an individual roller and it also forms twomoregrinding faces, one between the roller and the front die 22 and onebetween the die 23 and the main bottom dies in the pan. Each grindingunit, consisting of a roller and a shoe, is, therefore, provided withfour separate and independent grinding faces. First,

to the capacity of the in shaft, it can readily be seen that they 4 themain oute surface of the roller engages the bottom dies while rollingaround the pan; second, the outer beveled end of each roller engageswith the annularly arranged end dies l, thereby forming a second grind-111g surface; third, the die 22 engages the The pivotal mounting of eachshoe with relation to the driving arm 12 permits the whole weight of theshoe and the dies carried thereby to be exerted upon the dies 23 and themain bottom dies 4. This is of considerable importance as it permits thematerial treated to be finely ground by the grinding action of the shoe.The pivot pins, by which the shoes are connected to the arms, arepreferably passed through slots 24 formed in the lower ends of the armsto permit each shoe to rise and fall, or, in other words, adjust itselfto the quantity of material deliveredto the pan. The lower edge of thedie 22 and the front edge of the die 23 are preferably tapered off, asshown at 25, to permit the admission of material between the grindingfaces, and as they are both removable and renewable, it can readily beseen that the life of each shoe is practically unlimited. This is alsotrue as far as the rollers are concerned; that is, a roller shell 18when worn too thin may easily be renewed by removing it from the coreand applying a new shell which is secured by means of wooden or metalbushings, as shown at 26.

In actual operation, it has been. found that the outward or centrifugalforce exerted when the rollers are traveling at a certain speedenormously increases the grinding capacity between the ends of therollers and the dies 4. This, together with the several other grindingsurfaces provided, insures an unprecedented capacity and as adischarging screen 30, also having a large capacit extending around thepan is provided, it can be seen that the free discharge of the materialground will always be permitted.

The screen may be made in several sections which are secured in framessupported in channels 31 formed in the arms 5. They can be easilyremoved, when desired, and a line meshed screen can at the same time beprovided as each screen section or frame is comparatively small. 7

A mill constructed as here shown is simple in construction and isexceedingly'com pact insize for the quantity of 'material handled. Thelife of the mill is furthermore practically unlimited as all wearingparts, such as rollers and dies, may be renewed, when desired, and as noournals and lubricatlon are required, as far as the rollcm areconcerned, it can readily be seen that the cost of manufacture isfurthermore materially reduced. The screen discharge is all around themill housing instead of in one-half, as is ordinarily the case, and asthe feed hopper is centrally disposed an equal distribution anddischarge of the ore in front of each roller is permitted, consequentlycausing an even wear of the rollers and dies.

The materials and finish of the several. parts of the device are such asthe experience and judgment of the manufacturer may dictate.

I wish it understood that various changes in form, proportions and minordetails of construction may be resorted to within the scope of theappended claims and that I do not wish to limit myself to the specificdesign and construction here shown.

Having thus described my invention, what I claim and desire to secure byLetters Patent is- 1. In a grinding mill, a circular grinding pan, adriving shaft, a plurality of propelling arms secured on the shaft, saidarms being slotted at their outer ends, a dragshoe for each armengageable with the pan, and a pin on each shoe passing through the slotin each arm to permit a vertical and pivotal movement of each shoe withrelation to its propelling arm.

2. In a grinding mill, a circular grinding pan, a driving shaft, aplurality of propelling arms secured on the shaft, a drag-shoe pivotallyconnected to each arm and engageable with the pan, and a grinding rolleradapted to be propelled by each shoe.

3. In a grinding mill, a circular grinding pan, a driving shaft, aplurality of propelling arms secured on the shaft, a drag-shoe pivotallyconnected to each arm and engageable with the pan, and a freely mountedgrinding roller positioned forward of each shoe adapted to be propelledby each shoe.

4. In a grinding mill, a circular "rinding pan, a driving shaft, aplurality of propelling arms secured on the shaft, said arms beingslotted at their outer ends, a drag-shoe for each arm engageable withthe pan, a pin on each shoe passing through the slot in each arm topermit a vertical and pivotal movement of each shoe with relation to itspropelling arm, a freely running roller forward ofeach shoe and anupright section on the front end of each shoe engageable with a rollerfirst to form a grinding surface between each upright section and eachroller and secondly to push each roller around the pan ahead of theshoes.

5. In a centrifugal. roller mill, a circular women or thin patent may beobtained for five cents each, by addressing the cured to the forwardface of the upright section engageable with a roller, and a die platesecured to the lower face of the horizontal section engageable with thebottom dies.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

GEORGE C. RICHARDS. Witnesses:

JOHN H. HERRING, W. W. HEALEY.

Commissioner of Pntentn,

Washington, D. G.

